/*
 * %W% %E%
 *
 * Copyright (c) 2009, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package java.net;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.InterruptedIOException;
import java.io.FileDescriptor;
import java.io.ByteArrayOutputStream;

import sun.net.ConnectionResetException;

/**
 * Default Socket Implementation. This implementation does
 * not implement any security checks.
 * Note this class should <b>NOT</b> be public.
 *
 * @author  Steven B. Byrne
 * @version %I%, %G%
 */
class PlainSocketImpl extends SocketImpl
{
    /* instance variable for SO_TIMEOUT */
    int timeout;   // timeout in millisec
    // traffic class
    private int trafficClass;

    private boolean shut_rd = false;
    private boolean shut_wr = false;
    
    private SocketInputStream socketInputStream = null;

    /* number of threads using the FileDescriptor */
    private int fdUseCount = 0;

    /* lock when increment/decrementing fdUseCount */
    private Object fdLock = new Object();

    /* indicates a close is pending on the file descriptor */
    private boolean closePending = false;

    /* indicates connection reset state */
    private int CONNECTION_NOT_RESET = 0;
    private int CONNECTION_RESET_PENDING = 1;
    private int CONNECTION_RESET = 2;
    private int resetState;
    private Object resetLock = new Object();

    /* second fd, used for ipv6 on windows only.
     * fd1 is used for listeners and for client sockets at initialization
     * until the socket is connected. Up to this point fd always refers
     * to the ipv4 socket and fd1 to the ipv6 socket. After the socket
     * becomes connected, fd always refers to the connected socket 
     * (either v4 or v6) and fd1 is closed.
     *
     * For ServerSockets, fd always refers to the v4 listener and 
     * fd1 the v6 listener.
     */
    private FileDescriptor fd1;
    /*
     * Needed for ipv6 on windows because we need to know
     * if the socket is bound to ::0 or 0.0.0.0, when a caller
     * asks for it. Otherwise we don't know which socket to ask.
     */
    private InetAddress anyLocalBoundAddr=null;
 
    /* to prevent starvation when listening on two sockets, this is
     * is used to hold the id of the last socket we accepted on.
     */
    private int lastfd = -1;

    /**
     * Load net library into runtime.
     */
    static {
	java.security.AccessController.doPrivileged(
		  new sun.security.action.LoadLibraryAction("net"));
	initProto();
    }

    /**
     * Constructs an empty instance.
     */
    PlainSocketImpl() { }

    /**
     * Constructs an instance with the given file descriptor.
     * Note, this will not work with IPv6, since two fds are used.
     */
    PlainSocketImpl(FileDescriptor fd) {
	this.fd = fd;
    }

    /**
     * Creates a socket with a boolean that specifies whether this
     * is a stream socket (true) or an unconnected UDP socket (false).
     */
    protected synchronized void create(boolean stream) throws IOException {
	fd = new FileDescriptor();
	fd1 = new FileDescriptor();
	socketCreate(stream);
	if (socket != null)
	    socket.setCreated();
	if (serverSocket != null)
	    serverSocket.setCreated();
    }

    /**
     * Creates a socket and connects it to the specified port on
     * the specified host.
     * @param host the specified host
     * @param port the specified port
     */
    protected void connect(String host, int port)
        throws UnknownHostException, IOException
    {
	IOException pending = null;
	try {
	    InetAddress address = InetAddress.getByName(host);

	    try {
		connectToAddress(address, port, timeout);
		return;
	    } catch (IOException e) {
		pending = e;
	    }
	} catch (UnknownHostException e) {
	    pending = e;
	}

	// everything failed
	close();
	throw pending;
    }

    /**
     * Creates a socket and connects it to the specified address on
     * the specified port.
     * @param address the address
     * @param port the specified port
     */
    protected void connect(InetAddress address, int port) throws IOException {
	this.port = port;
	this.address = address;

	try {
	    connectToAddress(address, port, timeout);
	    return;
	} catch (IOException e) {
	    // everything failed
	    close();
	    throw e;
	}
    }

    /**
     * Creates a socket and connects it to the specified address on
     * the specified port.
     * @param address the address
     * @param timeout the timeout value in milliseconds, or zero for no timeout.
     * @throws IOException if connection fails
     * @throws  IllegalArgumentException if address is null or is a
     *          SocketAddress subclass not supported by this socket
     * @since 1.4
     */
    protected void connect(SocketAddress address, int timeout) throws IOException {
	if (address == null || !(address instanceof InetSocketAddress))
	    throw new IllegalArgumentException("unsupported address type");
	InetSocketAddress addr = (InetSocketAddress) address;
	if (addr.isUnresolved())
	    throw new UnknownHostException(addr.getHostName());
	this.port = addr.getPort();
	this.address = addr.getAddress();

	try {
	    connectToAddress(this.address, port, timeout);
	    return;
	} catch (IOException e) {
	    // everything failed
	    close();
	    throw e;
	}
    }

    private void connectToAddress(InetAddress address, int port, int timeout) throws IOException {
	if (address.isAnyLocalAddress()) {
	    doConnect(InetAddress.getLocalHost(), port, timeout);
	} else {
	    doConnect(address, port, timeout);
	}
    }

    public void setOption(int opt, Object val) throws SocketException {
	if (isClosedOrPending()) {
	    throw new SocketException("Socket Closed");
	}
	boolean on = true;
	switch (opt) {
	    /* check type safety b4 going native.  These should never
	     * fail, since only java.Socket* has access to
	     * PlainSocketImpl.setOption().
	     */
	case SO_LINGER:
	    if (val == null || (!(val instanceof Integer) && !(val instanceof Boolean)))
		throw new SocketException("Bad parameter for option");
	    if (val instanceof Boolean) {
		/* true only if disabling - enabling should be Integer */
		on = false;
	    }
	    break;
	case SO_TIMEOUT:
	    if (val == null || (!(val instanceof Integer)))
		throw new SocketException("Bad parameter for SO_TIMEOUT");
	    int tmp = ((Integer) val).intValue();
	    if (tmp < 0)
		throw new IllegalArgumentException("timeout < 0");
	    timeout = tmp;
	    break;
	case IP_TOS:
	     if (val == null || !(val instanceof Integer)) {
		 throw new SocketException("bad argument for IP_TOS");
	     }
	     trafficClass = ((Integer)val).intValue();
	     break;
	case SO_BINDADDR:
	    throw new SocketException("Cannot re-bind socket");
	case TCP_NODELAY:
	    if (val == null || !(val instanceof Boolean))
		throw new SocketException("bad parameter for TCP_NODELAY");
	    on = ((Boolean)val).booleanValue();
	    break;
	case SO_SNDBUF:
	case SO_RCVBUF:
	    if (val == null || !(val instanceof Integer) ||
		!(((Integer)val).intValue() > 0)) {
		throw new SocketException("bad parameter for SO_SNDBUF " +
					  "or SO_RCVBUF");
	    }
	    break;
	case SO_KEEPALIVE:
	    if (val == null || !(val instanceof Boolean))
		throw new SocketException("bad parameter for SO_KEEPALIVE");
	    on = ((Boolean)val).booleanValue();
	    break;
	case SO_OOBINLINE:
	    if (val == null || !(val instanceof Boolean))
		throw new SocketException("bad parameter for SO_OOBINLINE");
	    on = ((Boolean)val).booleanValue();
	    break;
	case SO_REUSEADDR:
	    if (val == null || !(val instanceof Boolean)) 
	        throw new SocketException("bad parameter for SO_REUSEADDR");
	    on = ((Boolean)val).booleanValue();
	    break;
	default:
	    throw new SocketException("unrecognized TCP option: " + opt);
	}
	socketSetOption(opt, on, val);
    }
    public Object getOption(int opt) throws SocketException {
	if (isClosedOrPending()) {
	    throw new SocketException("Socket Closed");
	}
	if (opt == SO_TIMEOUT) {
	    return new Integer(timeout);
	}
	int ret = 0;
	/*
	 * The native socketGetOption() knows about 3 options.
	 * The 32 bit value it returns will be interpreted according
	 * to what we're asking.  A return of -1 means it understands
	 * the option but its turned off.  It will raise a SocketException
	 * if "opt" isn't one it understands.
	 */

	switch (opt) {
	case TCP_NODELAY:
	    ret = socketGetOption(opt, null);
	    return Boolean.valueOf(ret != -1);
	case SO_OOBINLINE:
	    ret = socketGetOption(opt, null);
	    return Boolean.valueOf(ret != -1);
	case SO_LINGER:
	    ret = socketGetOption(opt, null);
	    return (ret == -1) ? Boolean.FALSE: (Object)(new Integer(ret));
	case SO_REUSEADDR:
	    ret = socketGetOption(opt, null);
	    return Boolean.valueOf(ret != -1);
	case SO_BINDADDR:
	    if (fd != null && fd1 != null ) {
		/* must be unbound or else bound to anyLocal */
		return anyLocalBoundAddr;
	    }
	    InetAddressContainer in = new InetAddressContainer();
	    ret = socketGetOption(opt, in); 
	    return in.addr;
	case SO_SNDBUF:
        case SO_RCVBUF:
	    ret = socketGetOption(opt, null);
	    return new Integer(ret);
	case IP_TOS:
	    ret = socketGetOption(opt, null);
	    if (ret == -1) { // ipv6 tos
		return new Integer(trafficClass);
	    } else {
		return new Integer(ret);
	    }
	case SO_KEEPALIVE:
	    ret = socketGetOption(opt, null);
  	    return Boolean.valueOf(ret != -1);
	// should never get here
	default:
	    return null;
	}
    }

    /**
     * The workhorse of the connection operation.  Tries several times to
     * establish a connection to the given <host, port>.  If unsuccessful,
     * throws an IOException indicating what went wrong.
     */

    private synchronized void doConnect(InetAddress address, int port, int timeout) throws IOException {
        try {
	    FileDescriptor fd = acquireFD();
	    try {
	        socketConnect(address, port, timeout);
	        /* socket may have been closed during poll/select */
	        synchronized (fdLock) {
	            if (closePending) {
	                throw new SocketException ("Socket closed");
	            }
	        }
		// If we have a ref. to the Socket, then sets the flags
		// created, bound & connected to true.
		// This is normally done in Socket.connect() but some
		// subclasses of Socket may call impl.connect() directly!
		if (socket != null) {
		    socket.setBound();
		    socket.setConnected();
		}
	    } finally {
		releaseFD();
	    }
	} catch (IOException e) {	
	    close();
	    throw e;
	}
    }

    /**
     * Binds the socket to the specified address of the specified local port.
     * @param address the address
     * @param port the port
     */
    protected synchronized void bind(InetAddress address, int lport)
	throws IOException
    {
	socketBind(address, lport);
	if (socket != null)
	    socket.setBound();
	if (serverSocket != null)
	    serverSocket.setBound();
	if (address.isAnyLocalAddress()) {
	    anyLocalBoundAddr = address;
	}
    }

    /**
     * Listens, for a specified amount of time, for connections.
     * @param count the amount of time to listen for connections
     */
    protected synchronized void listen(int count) throws IOException {
	socketListen(count);
    }

    /**
     * Accepts connections.
     * @param s the connection
     */
    protected synchronized void accept(SocketImpl s) throws IOException {
	FileDescriptor fd = acquireFD();
	try {
	    socketAccept(s);
	} finally {
	    releaseFD();
	}
    }

    /**
     * Gets an InputStream for this socket.
     */
    protected synchronized InputStream getInputStream() throws IOException {
	if (isClosedOrPending()) {
	    throw new IOException("Socket Closed");
	}
	if (shut_rd) {
	    throw new IOException("Socket input is shutdown");
	}
	if (socketInputStream == null) {
	    socketInputStream = new SocketInputStream(this);
	}
	return socketInputStream;
    }

    void setInputStream(SocketInputStream in) {
	socketInputStream = in;
    }

    /**
     * Gets an OutputStream for this socket.
     */
    protected synchronized OutputStream getOutputStream() throws IOException {
	if (isClosedOrPending()) {
	    throw new IOException("Socket Closed");
	}
        if (shut_wr) {
	    throw new IOException("Socket output is shutdown");
	}
	return new SocketOutputStream(this);
    }

    /**
     * Returns the number of bytes that can be read without blocking.
     */
    protected synchronized int available() throws IOException {
	if (isClosedOrPending()) {
            throw new IOException("Stream closed.");
	}

	/*
	 * If connection has been reset then return 0 to indicate
	 * there are no buffered bytes.
	 */
	if (isConnectionReset()) {
	    return 0;
	}

	/*
	 * If no bytes available and we were previously notified
	 * of a connection reset then we move to the reset state.
	 *
	 * If are notified of a connection reset then check
	 * again if there are bytes buffered on the socket. 
	 */
	int n = 0;
	try { 
	    n = socketAvailable();
	    if (n == 0 && isConnectionResetPending()) {
	        setConnectionReset();
	    }
	} catch (ConnectionResetException exc1) {
	    setConnectionResetPending();
	    try {
	        n = socketAvailable();
		if (n == 0) {
		    setConnectionReset();
		}
	    } catch (ConnectionResetException exc2) {
	    }
	}
	return n;
    }

    /**
     * Closes the socket.
     */
    protected void close() throws IOException {
	synchronized(fdLock) {
	    if (fd != null || fd1 != null) {
		if (fdUseCount == 0) {
		    if (closePending) {
			return;
		    }
		    closePending = true;
		    /*
		     * We close the FileDescriptor in two-steps - first the
 		     * "pre-close" which closes the socket but doesn't
		     * release the underlying file descriptor. This operation
		     * may be lengthy due to untransmitted data and a long
		     * linger interval. Once the pre-close is done we do the
		     * actual socket to release the fd.
		     */
		    try {
		        socketPreClose();
		    } finally {
		        socketClose();
		    }
		    fd = null;
		    fd1 = null;
		    return;
		} else {
		    /*
		     * If a thread has acquired the fd and a close
		     * isn't pending then use a deferred close.
		     * Also decrement fdUseCount to signal the last
		     * thread that releases the fd to close it.
		     */
		    if (!closePending) {
			closePending = true;
		        fdUseCount--;
			socketPreClose();
		    }
		}
	    }
	}
    }
    
    void reset() throws IOException {
        if (fd != null || fd1 != null) {
            socketClose();
        }
        fd = null;
        fd1 = null;
        super.reset();
    }


    /**
     * Shutdown read-half of the socket connection;
     */
    protected void shutdownInput() throws IOException {
      if (fd != null) {
	  socketShutdown(SHUT_RD);
	  if (socketInputStream != null) {
	      socketInputStream.setEOF(true);
	  }
	  shut_rd = true;
      }
    } 

    /**
     * Shutdown write-half of the socket connection;
     */
    protected void shutdownOutput() throws IOException {
      if (fd != null) {
	  socketShutdown(SHUT_WR);
	  shut_wr = true;
      }
    } 

    protected boolean supportsUrgentData () {
        return true;
    }

    protected void sendUrgentData (int data) throws IOException {
        if (fd == null) {
            throw new IOException("Socket Closed");
        }
        socketSendUrgentData (data);
    }

    /**
     * Cleans up if the user forgets to close it.
     */
    protected void finalize() throws IOException {
	close();
    }


    /*
     * "Acquires" and returns the FileDescriptor for this impl
     *
     * A corresponding releaseFD is required to "release" the
     * FileDescriptor.
     */
    public final FileDescriptor acquireFD() {
	synchronized (fdLock) {
	    fdUseCount++;
	    return fd;
	}
    }

    /*
     * "Release" the FileDescriptor for this impl. 
     *
     * If the use count goes to -1 then the socket is closed.
     */
    public final void releaseFD() {
	synchronized (fdLock) {
	    fdUseCount--;
	    if (fdUseCount == -1) {
		if (fd != null) {
	            try {
			socketClose();
	            } catch (IOException e) { 
		    } finally {
		        fd = null;
		    }
		}
	    }
	}
    }

    public boolean isConnectionReset() {
	synchronized (resetLock) {
	    return (resetState == CONNECTION_RESET);
	}
    }

    public boolean isConnectionResetPending() {
	synchronized (resetLock) {
            return (resetState == CONNECTION_RESET_PENDING);
        }
    }

    public void setConnectionReset() {
	synchronized (resetLock) {
            resetState = CONNECTION_RESET;
        }
    }

    public void setConnectionResetPending() {
	synchronized (resetLock) {
            if (resetState == CONNECTION_NOT_RESET) {
                resetState = CONNECTION_RESET_PENDING;
            }
        }

    }

    /*
     * Return true if already closed or close is pending
     */
    public boolean isClosedOrPending() {
	/*
	 * Lock on fdLock to ensure that we wait if a
	 * close is in progress.
	 */
	synchronized (fdLock) {
	    if (closePending || (fd == null && fd1 == null)) {
		return true;
	    } else {
		return false;
	    }
	}
    }

    /*
     * Return the current value of SO_TIMEOUT
     */
    public int getTimeout() {
	return timeout;
    }

    /*
     * "Pre-close" a socket by dup'ing the file descriptor - this enables
     * the socket to be closed without releasing the file descriptor.
     */
    private void socketPreClose() throws IOException {
	socketClose0(true);
    }

    /*
     * Close the socket (and release the file descriptor).
     */
    private void socketClose() throws IOException {
	socketClose0(false);
    }

    private native void socketCreate(boolean isServer) throws IOException;
    private native void socketConnect(InetAddress address, int port, int timeout)
	throws IOException;
    private native void socketBind(InetAddress address, int port)
	throws IOException;
    private native void socketListen(int count)
	throws IOException;
    private native void socketAccept(SocketImpl s)
	throws IOException;
    private native int socketAvailable()
	throws IOException;
    private native void socketClose0(boolean useDeferredClose)
	throws IOException;
    private native void socketShutdown(int howto)
	throws IOException;
    private static native void initProto();
    private native void socketSetOption(int cmd, boolean on, Object value)
	throws SocketException;
    private native int socketGetOption(int opt, Object iaContainerObj) throws SocketException;
    private native int socketGetOption1(int opt, Object iaContainerObj, FileDescriptor fd) throws SocketException;
    private native void socketSendUrgentData(int data)
        throws IOException;

    public final static int SHUT_RD = 0;
    public final static int SHUT_WR = 1;
}

class InetAddressContainer {
    InetAddress addr;
}
